program Convex;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var
  n, i, k, q, tmp: integer;
  ax, ay: array of integer;
begin
  readln(n);
  setlength(ax,n);
  setlength(ay,n);
  for i:=0 to n-1 do
  begin
    read(ax[i]);
    read(ay[i]);
    readln;
  end;
  k:=ax[n-2]*ay[n-1]-ax[n-1]*ay[n-2]+ax[n-1]*ay[0];
  k:=k-ax[0]*ay[n-1]+ax[0]*ay[n-2]-ax[n-2]*ay[0];
  q:=ax[n-1]*ay[0]-ax[0]*ay[n-1]+ax[0]*ay[1];
  q:=q-ax[1]*ay[0]+ax[1]*ay[n-1]-ax[n-1]*ay[1];
  if (k*q<0) then
    writeln('It is not convex')
  else
  begin
    for i:=0 to n-3 do
    begin
      tmp:=ax[i]*ay[i+1]-ax[i+1]*ay[i]+ax[i+1]*ay[i+2];
      tmp:=tmp-ax[i+2]*ay[i+1]+ax[i+2]*ay[i]-ax[i]*ay[i+2];
      if (k*tmp<0) then
      begin
        writeln('It is not convex');
        break;
      end;
      if (i=n-3) then
        writeln('It is convex');
      end;
    end;
  readln;
end.
